IIRC (and I haven’t given any attention to SDI in almost eight years), it wasn’t ever shown that SDI could even be 5% effective, much less 50%. IMHO, the Soviets, having a lot of problems not directly related to the arms race (aging infrastructure, lack of a consumer economy, poor productivity, etc.; all drawbacks of a command economy), fell for a terrific con job.
About SDI… I’m sure that everyone’s heard the conspiracy theories that it was all successful, and the gov’t doesn’t want anyone to know. I’m pretty sure that’s bunk, of course, but I’m also pretty sure it wasn’t the failure that it was made out to be. I’d imagine that, just based on the HUGE amount of money that was spent on it, they figured SOMEthing out.
NOW BACK TO THE OP…
If we ever want to get anywhere with regards to space travel, then nuclear power would be the way to go. Ideally, the matter-antimatter reaction that is so popular in Star Trek would be the best, but since we have no means of achieving such a power source, I’d imagine plutonium would be ideal.
I’m not one who believes that humanity will begin mass-colonization within the next century, but I DO believe that we’ll place some sort of settlement on Mars, or even on one of the moons of Saturn. In addition to research stations, I’d also imagine mining facilities being set up. We’d need a strong power source to go back and forth.
The anti-nuke crowd seems to be against using nuclear power in space because of a lot of misconceptions… mostly, the false notion that uranium/plutonium works just like nitroglycerin, and just needs a good jolt to set it off. In order to set off a nuclear bomb, the fuel (plutonium) is put into a spherical container completely surrounded by, basically, blasting caps. Each of these blasting caps has to go off, at the exact same time, in order to compress the fuel together, setting off the stray neutrons that break apart the plutonium atoms, and create the big boom. (I’m sure I got some of the specifics here wrong… somebody correct me if I am?)
Thermonuclear explosions (fusion) are created by using the above process as a trigger, and the hydrogen fuel is stored in a sort of cone right next to the fission bomb. When the fission bomb is activated, the shockwave compresses the cone, causing the contents to fuse together into helium (and other such fun stuff… again, I may have gotten the specifics wrong).
Anyway, the thought that a crashing nuclear-powered spacecraft could obliterate a city is preposterous and kind of insulting. First off, the odds of such a spacecraft crashing are slim to none, and even so, there are numerous safeguards in place. You’d have to be TRYING to spill open the fuel containers in order to spread plutonium all over.
::jumps off the soapbox:: Who’s next? It’s really quite nice up there. It has a cool breeze, and I can see my house.
I’d heard (from an unreliable source) that there was an ABM proposal for ground-based missiles armed with big blasts of either shotgun pellets or sand. When we detected an enemy launch, we’d launch these shotgun missiles until they were just up out of the atmosphere, whereupon they’d detonate and scatter their loads in the paths of the incoming ICBMs. At the kinds of relative speeds that sand or shotgun pellets could achieve without the atmosphere in the way, one or two pellet hits would be enough to incapacitate any incoming missile.
This same unreliable source claims that the inventor of this system tried to sell it to both the U.S. and the U.S.S.R., but neither side was interested because it was too inexpensive and too effective to keep their country’s aerospace industry / military-industrial complex employed.
You wanna dabble in rumors, huh? How’s this… a friend claims to have seen, with his own eyes, plans for a 747 with a giant laser built into the nose. The idea was that this 747 would effectively have unlimited range, and would be able to shoot down anything over the horizon.
I managed to keep myself from laughing in his face when I heard this. The whole thing reminded me too much of Dr. Evil. “We will use this… ‘seven-forty-seven’… to shoot down any nuclear missiles and steal Austin Power’s mojo! Come, Mini-me, give me a backrub!”